Nifty trick for this difficult question:

Add +1 to both sides of the inequality in (1). You get:

r/(b+w) +1 > w/(b+r) +1

combine the 1 with the fractions on either side:

r+(b+w) / b+w > w+(b+r) / (b+r)

Note that the numerators are now the same r+b+w (the total number of options). Cross multiply to put that quantity in the bottom and make for a proper probability function:

(b+r)/ w+b+r > b+w / w+b+r
It follows that r>w, and the answer is yes.

Stat. (2) is insufficient with plugging in - you can find two opposing scenarios, where r is both smaller and greater than w, depending on the value of b.

Geva

Thanks a lot. With exams just a week away...anything that I 'm not able to solve gets me all worked up. After looking at your solution, the sum seems so simple....
Hope these things strike a chord when the D day comes.

cheers

Skywalker wrote:Geva

Thanks a lot. With exams just a week away...anything that I 'm not able to solve gets me all worked up. After looking at your solution, the sum seems so simple....
Hope these things strike a chord when the D day comes.

cheers

You're more than welcome.
Good luck on your test.